Conveyor chain for a stepmill

ABSTRACT

A conveyor chain which is designed to be used on a stepmill to form into steps on the side interacting with a user, and a stair climbing exercise device or “stairmill,” having a belt formed thereon. The belt being formed from a plurality of interconnected L-shaped elements each of the L-shaped elements having unequal arm and leg dimensions.

CROSS REFERENCE TO RELATED APPLICATION(S)

This Application claims the benefit of U.S. Provisional Patent Application Ser. No. 62/535,511, filed Jul. 21, 2017 and currently pending, the entire disclosure of which is incorporated herein by reference.

BACKGROUND 1. Field of the Invention

This disclosure relates to the field of cardiovascular exercise machines. In particular, to a conveyor chain for treadmills which are designed to provide a moving staircase (stairmills) and more particularly to a continuous belt comprised of L-shape elements for use with such.

2. Description of the Related Art

The benefits of regular aerobic exercise on individuals of any age are well documented in fitness science. Aerobic exercise can dramatically improve cardiac stamina and function, as well as lead to weight loss, increased metabolism, and other benefits. At the same time, aerobic exercise has often been linked to damaging effects, particularly to joints or similar structures, where the impact from many aerobic exercise activities can cause injury. Therefore, those involved in the exercise industry are continuously seeking ways to provide users with exercises that have all the benefits of aerobic exercise, without the damaging side effects.

One relatively low impact exercise is walking. Walking has a number of advantages over its faster relative, running. In particular, walking causes much less stress on body structures in the legs, feet, and hips. In a walking motion, the human body generally never completely leaves the ground while, in a running motion, the body is suspending midair for a short period of time with each stride. Thus, while walking, knees and other structures absorb an impact from the foot's contact with a surface, but the entire weight of the individual is generally not absorbed by the body as it is in running. For this reason, walking is generally an acceptable exercise for a large number of people and even for the elderly and those with joint or other issues. Further, the impact of walking can be further reduced by walking on a treadmill or other exercise device as opposed to walking outside. The tread of a treadmill can be purposefully engineered to absorb and reduce impact from footfalls, making the walking motion produce even less impact on the body.

Walking as an exercise, however, has a number of built-in limitations and these can be exaggerated when one is intending to walk on a machine in the home or gym such as a treadmill. Many of the problems relate to walking's built in limitations for strenuousness. The average human will generally naturally walk around 3 to 3.5 miles per hour and most humans cannot walk above 4 to 5 miles per hour without specific training. Generally, at higher speeds, the person has to switch to a running motion in order to maintain the desired speed. It is often accepted that speeds between 4 and 6 miles per hour require the average human to jog, while speeds above 6 miles per hour require a running motion. Humans can obtain very fast speeds while running with an average person being able to sprint at over 10 miles per hour. Further, some studies have indicated that any person's natural walking speed may be preferentially selected to minimize work for desired distance and time. Thus, natural walking as an exercise can be problematic because humans may naturally walk in a very efficient fashion, which can minimize its exercise potential.

While a sustained walking speed of 4 mph can prove plenty strenuous for many people, for those looking for weight loss and strong cardiovascular workouts, walking, even at their top sustainable speed, can require a very long workout to be equivalent to a relatively short run and the time for such a workout may not be available. The time required by walking can be particularly problematic for home exercise machines where the average user can find walking in-place for a long period of time boring since there is no changing scenery or people to talk to.

For those who are interested in using an exercise machine for strenuous walking, the common way to increase the strenuousness of the activity is to increase the incline of the tread forcing them to consistently walk “uphill” or engage in more of a hiking or climbing exercise. Walking at even a relatively slight angle above neutral (or level) has been shown to dramatically increase the strenuousness of the walking. However, traditional treadmills often have problems producing higher inclines. Specifically, traditional treadmills could generally only obtain a maximum incline of around 10-15 percent.

To go to higher inclines, many workout machines will transition from the standard smooth running belt of a treadmill to a conveyor chain that is designed to simulate steps. These are often referred to as “stepmills”. The act of going up stairs has been long known to be a vigorous exercise because it not only requires moving the body (where moving the body mass provides the resistance) horizontally, but vertically in a near equal amount. Further, walking up a staircase as an exercise generally causes the person doing it to work multiple of their large lower body muscles. This is an effective way to burn calories, build muscle mass, and sculpt one's appearance. Further, stair climbing also assists in working on balance since the person's mass is generally being lifted by a single leg at a time and provides an intense cardio workout due to its difficulty.

Originally, those interested in performing stair workouts would simply utilize a convenient flight of stairs. Probably the most memorable stair workout occurs in the movie “Rocky” with Rocky Balboa running up the 72 stone steps in front of the Philadelphia Museum of Art to evocative music and raising his hands in triumph at the end. That scene, which is considered by many as one of the greatest scenes in movie making, may have even served as the inspiration for a resurgence in stair climbing as an exercise. Even today, stair-climbing races are popular fundraisers in a number of cities and many fitness trackers will separately track stair climbing.

While running or walking up an actual staircase can be a highly effective workout, it does present a reasonably high danger of falling, can be of limited interest and availability due to a limited number of stair steps available in a home or even gym setting, and can be difficult in inclement weather if the staircase is outside. For that reason, the concept of stepmills seek to provide what is essentially an endless staircase indoors to allow for a similar exercise to be performed in limited space and over a longer period of time.

Originally, stepmills operated along the same basic principle as the escalator moving stairway which is a venerable design generally considered in its modern form to date back over 100 years and in older forms almost 200 as evidenced by documents such as U.S. Pat. Nos. 25,076; 406,314; and 479,864. People just simply use the structure of escalators in reverse by attempting to walk up a staircase that is actually moving down. The stair operation of many stepmills has also been traditionally similar where the stairs each comprise a solid component “block” mounted on a chain. Each of the blocks is generally triangular in cross-section and includes a generally 90-degree corner on the user facing side with one of the faces on the opposing side. A chain is then used to interconnect and mount the faces together. In this way, when the chain is arranged at an angle, the blocks form a series of steps. A user is supported on the chain by simply supporting the blocks on a truss system and platform that serves to hold the user's body weight.

While this structure is highly effective for an escalator to move people between floors of a building, it actually has some major problems in conjunction with an exercise device. The most notable of which is its vertical size. Because the stair chain needs to be an endless loop, the height of a stepmill chain is generally substantial. In particular, the base is commonly quite high off the ground as the chain and blocks need to clear the floor a sufficient distance to allow the full size of each block to not impact the floor as it goes around under the device and under the chain part being used. Further, the top portion of the device is generally defined by the number of steps the device has. As a step is commonly between 8 and 12 inches, to have even a small number of steps be available to the user (for example 4), the top of the top block will commonly be more than 4 feet off the ground. To deal with this some manufacturers broke the step into two components, a tread and a kickplate, which could rotate about each other but were individually quite thin. While this allowed the components to generally arrange themselves in a more co-planar arrangement when returning under the step arrangement, the original height still had to be sufficient to allow the kickplate and tread to turn the bottom corner closest to the floor. Thus, while the initial height did not have to be double the stair rise, it was often still at least a single rise and often more.

A second problem created by these kind of stepmills is the difficulty in getting on and off them. In an escalator, the landing platform at the bottom is actually suspended above the working elements of the escalator and the escalator belt actually extends under the floor. This allows the belt to have a different angle at the discharge end that causes the blocks to slide together so their upper surfaces form a generally co-planar flat surface across multiple stairs. This allows a user to step on or off without having to step up or down. In a stepmill machine, however, this is generally not possible as the machine cannot be built into the floor, but needs to rest on the floor.

Thus, getting on the machine commonly requires a user to step up the distance of at least one, and often more, stairs to get on the machine. This can be uncomfortable. Further, it can create a fairly major safety situation as if a user was to inadvertently go too far back on the machine and the stair tilted out from under them as it went around the lower corner and began its turn to return to the top, the user has a rather substantial distance to fall off the lowest step which can lead to major injury.

Because of these and other similar problems, the stepmill fell out of favor for gyms and home exercise. Instead, it was replaced by a “stepper” or a machine that utilized pneumatic or hydraulic resisted levers to simulate stair movement in the legs. In these systems, the user would lift their foot on a lever that would then be pushed up by a piston at generally the same rate they moved against the base of their foot. Upon, reaching the top of the “step”, the user would then push the lever down against the piston to provide the exercise stroke, while simultaneously raising their other foot. In this way, a “high step” kind of motion similar to that of stair stepping was created. While this was an effective exercise, it was not actually stair climbing as the user did not actually lift their full mass with each step. Instead, the majority of resistance was actually provided by contracting the piston which their mass assisted with.

Stepper machines have also fallen out of favor due to them not being particularly comfortable to use since the motion is somewhat unnatural and have been replaced more by elliptical machines or standing bikes that utilize a rotational motion instead of the multiple levers reducing impact on the body but provide a similar “high step” type motion. The stepmill, however, has begun to see a comeback with one of its modern counterparts having become quite common. That is the endless ladder. The endless ladder is not climbing on stairs where the foot is placed on a flat horizontal surface, but by climbing on cylindrical rungs. As the rungs can be much smaller than the stair tread and can be circular in dimeter, the step of a rung is much smaller than a traditional step. This allows the base of the machine to be much closer to the ground. However, the motion of an endless ladder can be a bit uncomfortable and unnatural as one is commonly climbing at an angle and the user's full foot does not contact the rung. Further, because an endless ladder requires a user to use their hands on a “higher” rung to stabilize themselves, the tread of these devices are often very long meaning that while they may not have as much vertical height to horizontal height as a stepmill, they often require even more space to handle their large tread and rotating the base through multiple angles.

SUMMARY

The following is a summary of the invention in order to provide a basic understanding of some aspects of the invention. This summary is not intended to identify key or critical elements of the invention or to delineate the scope of the invention. The sole purpose of this section is to present some concepts of the invention in a simplified form as a prelude to the more detailed description that is presented later.

Because of these and other problems in the art, described herein, among other things, are devices, systems, and methods, pertaining to a stair climbing exercise device or “stairmill,” having a belt formed from a plurality of interconnected L-shaped elements each of the L-shaped elements having unequal arm and leg dimensions.

There is described herein, among other things, a conveyor chain for a stepmill, the chain comprising: a plurality of links, each of the links comprising: a first member and a second member arranged together at a joint forming a generally 90 degree angle, the first member having an edge spaced from the joint a first distance and the second member having an edge spaced from the joint a second distance different form the first; a first plurality of eyelets extending from the edge of the first member, the first plurality of eyelets alternating with a first plurality of gaps, each of the eyelets in the first plurality of eyelets having a hole therethrough; a second plurality of eyelets extending from the edge of the second member, the second plurality of eyelets alternating with a second plurality of gaps, each of the eyelets in the second plurality of eyelets having a hole therethrough; and a plurality of rods; wherein the plurality of links are positioned so that: the first plurality of eyelets on a first link are interleaved into the second plurality of gaps on a second link and a rod from the plurality of rods is placed through the holes in the first plurality of eyelets on the first link and the holes in the second plurality of eyelets on the second link; and the second plurality of eyelets on the first link are interleaved into the first plurality of gaps on a third link and a rod from the plurality of rods is placed through the holes in the second plurality of eyelets on the first link and the holes in the first plurality of eyelets on the third link.

In an embodiment of the conveyor chain, the plurality of links includes at least four links.

In an embodiment of the conveyor chain, the plurality of links includes at least eight links.

In an embodiment of the conveyor chain, each of the rods extends from the eyelets on both sides of the links.

In an embodiment of the conveyor chain, the plurality of links comprises an even number of links.

There is also described herein a stairmill comprising: a support structure; two tracks attached to the support structure at opposing sides of the support structure; and a conveyor chain comprising: a plurality of links, each of the links comprising: a first member and a second member arranged together at a joint forming a generally 90 degree angle, the first member having an edge spaced from the joint a first distance and the second member having an edge spaced from the joint a second distance different form the first; a first plurality of eyelets extending from the edge of the first member, the first plurality of eyelets alternating with a first plurality of gaps, each of the eyelets in the first plurality of eyelets having a hole therethrough; a second plurality of eyelets extending from the edge of the second member, the second plurality of eyelets alternating with a second plurality of gaps, each of the eyelets in the second plurality of eyelets having a hole therethrough; and a plurality of rods; wherein the plurality of links are positioned so that: the first plurality of eyelets on a first link are interleaved into the second plurality of gaps on a second link and a rod from the plurality of rods is placed through the holes in the first plurality of eyelets on the first link and the holes in the second plurality of eyelets on the second link; the second plurality of eyelets on the first link are interleaved into the first plurality of gaps on a third link and a rod from the plurality of rods is placed through the holes in the second plurality of eyelets on the first link and the holes in the first plurality of eyelets on the third link; and each of the rods in the plurality of rods includes a portion extending from the eyelets on each side of the links; wherein the rods include a roller bearing on each of the portions, one of the roller bearings on each rod rolling in each one of the two independent tracks.

In an embodiment of the stepmill, the plurality of links includes at least four links.

In an embodiment of the stepmill, the plurality of links includes at least eight links.

In an embodiment of the stepmill, the plurality of links comprises an even number of links.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view illustrating an embodiment of an L-shaped belt.

FIG. 2 is a perspective view illustrating an embodiment of an L-shaped belt element attached to other adjacent L-shaped belt elements in a stairmill belt according to the present disclosure.

FIG. 3 is a perspective view of a continuous stairmill belt formed from L-shaped belt elements according to the present disclosure.

FIG. 4 is a perspective view illustrating a stairmill having a continuous stairmill belt formed from L-shaped belt elements according to the present disclosure.

FIG. 5 is a detail perspective view of the base of the embodiment of FIG. 4.

FIG. 6 is a detail view of the bearing that supports the end of the rod in the track.

DESCRIPTION OF THE PREFERRED EMBODIMENT(S)

It is helpful to provide some general terminology that will be used herein. Generally, this disclosure is concerned with a conveyor chain that can be formed into stair steps. Stair steps are well understood by one of ordinary skill in the art and generally have two surfaces that are visible to a user, a “tread”, which is generally horizontal and upon which a user will place their foot when climbing the steps and a “kickplate” that serves to interconnect adjacent treads and provides the vertical separation between them. The kickplate also serves to prevent a user's foot from extending underneath the next tread. It should be recognized that is some forms of stairs, the kickplate is not present for aesthetic reasons. However, a stepmill will generally have a kickplate to eliminate a potential pinch hazard between adjacent treads and to provide for a continuous chain shape. Further, one of ordinary skill in the art generally understands what the top of a staircase is and the bottom of a staircase is.

A stepmill is an exercise device which provides for a moving belt or chain which provides a small staircase (generally having between 3 and 5 treads of steps) where the belt or chain which forms the steps can move backwards (downwards) making the staircase effectively endless. Stairs will generally become available to the user at the top of the staircase and the steps will disappear under the staircase at the bottom. The user will walk on treads that are within the middle which provide a sturdy base and generally hold their relative positions to each other.

To provide for the endless loop operation, the belt or chain of the stepmill causes the elements forming the staircase to return from the bottom of the staircase to the top of the staircase generally underneath the staircase as visible to the user. This makes the staircase “endless” from the point of view of the user. As the user steps up a step, the step simultaneously moves downward. Generally, the user will walk forwards up the staircase formed by a stepmill, but this is by no means required.

A conveyor chain of the type used in a stepmill is an endless loop comprising a series of links that are connected together. This is as opposed to a belt comprising a single looped piece of material. Each link of a conveyor chain will be connected to the next and prior link via a rotational connection with the first and last link interconnected to form a loop. This allows the links to freely rotate relative to each other. It should be recognized that links are considered to repeat in a chain, thus, a link may be made up of one or more components which also rotate relative to each other, but which do not repeat. That is, a “link” as used herein comprises one piece of the chain that, when multiple identical links are interconnected, form the conveyor chain. FIG. 4 provides an embodiment of a stairmill (101) utilizing a conveyor chain (103) made of L-shaped links (105).

FIG. 1 depicts an embodiment of one such L-shaped link (105). In the depicted embodiment of FIG. 1, the L-shaped link (105) comprises two members (117) and (119) connected at a joint (121). The connection is at about a 90-degree angle, giving the L-shaped link (105) an L-shaped cross-section. In the depicted embodiment, members (117) and (119) are approximately the same thickness and width, though they differ in length, with member (119) in the depicted embodiment of FIG. 1 extending further from joint (121) (being longer) than does member (117). Both depicted members (117) and (119) are generally in the configuration of an elongated rectangular prism having a plurality of eyelets (123) extending therefrom at an edge (217) and (219) opposing the joint (121).

As can be best seen in FIG. 2, the members (117) and (119), in the depicted embodiment, are rounded or smoothed along the width at joint (121). This can provide additional rigidity and strength as well as eliminating sharp edges and improving formability of the link (105) as a monolithic piece. It can further improve cleanliness of the link (105) by eliminating an internal sharp corner in which debris can become lodged and difficult to remove.

In the depicted embodiment, there are a plurality of eyelets (123) extending from each edge (217) and (219) which are alternated with a plurality of gaps (128) on each of members (117) and (119). Because members (117) and (119) are generally perpendicular, the eyelets (123) on each are also perpendicular from the eyelets (123) on the other. The depicted eyelets (123) generally have the configuration of a geometric half stadium, also known as a discorectangle or an obround, in cross-section. The eyelets (123) are disposed on each of members (117) and (119) such that the axis of symmetry for the half-stadium cross-section are generally about centered on the thickness of the member (117) and (119). As can be seen in FIG. 1, each set of eyelets (123) essentially gives the corresponding member (117) and (119) the appearance of a rounded end with a sequence or pattern of gaps or channels (128) therein.

As seen in FIG. 1, the eyelets (123) generally each contain a hole or bore (125) therethrough. On each member (117) or (119), these holes (125) are generally aligned along a linear axis (127) generally parallel to the major axis (or width) of member (117) and (119) so that a rod (129) can be inserted through all of them simultaneously as shown in FIG. 2. In the depicted embodiment of FIG. 1, a plurality of eyelets (123) is shown, but, in an embodiment, a singular protrusion may be provided. However, it is preferred, as described below in more detail, to include a plurality of protrusions.

The width (W₁) of each of the eyelets (123) in the depicted embodiment is about the same, but in an alternative embodiment, each eyelet (123) may have a different width, or may be organized into groups or sets of eyelets (123) with similar widths. It is generally preferred, however, that the widths of the eyelets (123) on each member (117) and (119) coordinate with the widths (W₂) of the gaps (128) in the other member (117) or (119). Further, it is generally preferred that the eyelets (123) be offset from center so that one side (201) of the link (105) has two eyelets (123) arranged thereon (one on each member (117) and (119)) and the opposing side (203) of the link (105) has two gaps (128) arranged thereon (again with one on each member (117) and (119)).

As shown in FIG. 2, the structure of the link (105) of FIG. 1 allows a single design of link (105B) to be laterally reversed and interconnected with a second link (105A) and third link (105C) of generally similar or identical construction of each member (117) and (119) of link (105B). That is, the width (W₁) of the eyelet (123) on member (119) on the far side (201) of the depicted embodiment of FIG. 1 should be about the same as the width of the gap (W₂) between the opposing end of member (117) and the first eyelet (123) on the near side (203) of the depicted embodiment of FIG. 1. Thus, the depicted link (105) of FIG. 1 may be laterally reversed (flipped over along the width), such that each eyelet (123) and gap (128) on member (119) will interlace with each eyelet (123) and gap (128) of member (117). So long as the pattern of corresponding eyelets (123) and gaps (128) repeats along the length of both members (117) and (119) in a manner such that the eyelets (123) on member (117) correspond to the gaps on (119) when the link (105) is reversed, and vice versa, this allows for the conveyor chain (101) to be formed from only one specific shape of link (105). This arrangement is best shown in FIGS. 2 and 3. This simplifies construction and reduces manufacturing costs by requiring only a single mold of link (105).

The length of members (117) and (119) may vary, but generally are configured such that when a first L-shaped link (105) is connected to a laterally reversed second L-shaped link (105), the combined length of the adjoined members (117) and (119) is an ergonomically comfortable stepping height (kickplate height) for a human, and an ergonomically comfortable stepping distance (tread length) for a human. As can be seen in FIG. 2 and also FIG. 3, it is generally preferred that the links (105) be arranged so that the kickplate of each stair have the longer member (119) arranged below the shorter member (117). This also provides that the longer member (119) forms the front of the tread (the portion furthest from the kickplate) while the shorter member (117) provides the rear (the portion closest to the kickplate). This arrangement can provide for increased stability of the stair as the tread is effectively supported at a distance more spaced under the tread as discussed later.

To form a stairmill belt (103), a plurality of L-shaped links (105) are connected together, in alternating fashion. That is, a first link (105A) is connected to a second link (105B), by laterally reversing the second link (105B) and fitting the eyelets (123) of the first link's (105A) member (117) of the second link (105B) to the corresponding gaps (128) of the second link's (105B) member (119), or vice versa as shown in FIG. 2. The bores (125) in the eyelets (123) of both members (117) and (119) all share a common center axis. A rod (129) is then threaded through the interlocking eyelets (123), allowing the two links (105A) and (105B) to swivel around the rod (129).

A third link (105C) is attached to the second link (105B) in similar fashion, and so on with additional elements (105D), (105E), (105F), (105G), (105H), (105I), (105J), (105K), (105L), (105M), (105N), (105P), and (105Q) to form a belt (103) as shown in FIG. 3. As is clear from FIG. 3, the link pattern generally utilizes an even number of L-shaped links (105), with every second link (105) having the same orientation. This produces the continuous stair belt (103) of FIG. 3.

To use the device (101) and move the belt (103), the belt (103) is generally mounted to a drive chain (111) on a frame (107). This configuration is shown in FIG. 4. In the depicted embodiment of FIG. 4, a belt (103) is mounted to a drive chain (111) on a frame (107), which supports the chain (111). The depicted embodiment includes a track (115) which accepts the rods through the bores and eyelets (123) as each successive link (105) section passes up the back of the device (101) and begin to descend to stepping position. As best shown in FIG. 6, a bearing (131) is on the end of the rod (129) to allow the rod (129) to be supported within the track (115).

The rod (129) and track (115) via the bearing (131) connection generally provide sufficient support for the body mass of the user and the impact forces of stepping. The stair belt (103) moves in a downward fashion from top to bottom under power of a traditional stepmill motor. The user uses the device (101) by stepping on each successive stair as it moves downward, simulating climbing a stair. When the lower-most L-shaped link (105) leaves the support track (115), the user will have already stepped off it, and the support is no longer necessary. This can be seen in FIG. 4, where the bottom-most link (105A) is no longer in use and has begun to rotate around the rod (129), leaving only half of a step formed by one link (105B). The user at this point is no longer stepping on link (105A) or (105B), and the support of the rod (129) in the track (115) is not needed.

As each link (105) passes up the back of the machine (101) and loops around the top gears into position, the rod (129) enters the support track (115) to provide the support. As can be seen, the rod (129) is also connected to the chain (111), which provides the movement of the belt (103) and generally the chain (111) will pass through the support track (115) or in close proximity to it.

As indicated previously, because each link (105) includes members (117) and (119) of unequal length, the make up of the tread of each step is a majority one link (105). As shown in FIG. 2, the longer length member (119) is generally positioned so as to form the front (furthest from the kickplate) portion of each step tread. This arrangement provides for increased strength to support the user. To illustrate this, one can consider the member (119) being substantially longer and the member (117) being substantially shorter. In this case, the bearing supporting the rod (129) in the kickplate would generally be fairly close and under the user's heel or arch when they step with the other bearing and rod in the tread would be in the back portion of the tread (closes to the kickplate) and either under the front half of their foot or in front of it. Thus, the user's mass will generally be primarily toward the front of the step (away from the kickplate) and between the location of the two rods (129).

The rod attaching member (117) to the chain is directly below the point where the prior kickplate meets the current tread. Thus, a user putting pressure on this part of the tread is well supported as that pressure will translate directly to the rod (129) and track (115). It should also be apparent that moving the rod attaching member (119) to the chain forward will provide an increase in horizontal distance between the pins meaning that the user's mass will generally primarily, if not completely, be located between the two pins (129) on either end of one link (105). The force of the user into the tread is thus divided between the two pins (129) making the chain (111) and tread feel better supported. As a user tends to have their mass supported on the front half of each tread, it is therefore desirable that the rod attaching member (119) to the chain (111) be located backward (toward the kickplate) of the midpoint of the tread.

In the depicted embodiment, the frame (107) further comprises a plurality of adjustable feet (109), which both provide friction with the floor, and prevent damage to the floor by the motion of the machine, such as through scratching. These feet (109) may also be adjustable to level and balance the device (101) on an uneven surface. The depicted embodiment further comprises handle bars to assist the user in getting on and off the device, or recovering his or her balance in the event of a fall.

The frame (107) may also be attached to additional frame components (not shown) which are used to provide hand grips, arm drives, lift mechanisms, support feet, and other related frame components and elements as known to those of ordinary skill in the art to provide functionality and usability to treadmills and other exercise machines.

There will also generally be attached to the frame (107) a computer system (not shown), which is connected to a user interface. The user interface may be as simple as dials or buttons, or may be more complex, including touch-activated screens and other computer-like interface features. When a user pushes buttons on the interface or the screen, electrical signals are sent to electrical components of the system such as sensors or motors to control the belt (103)

Throughout this disclosure, relative terms such as “generally,” “about,” and “approximately” may be used, such as, but not necessarily limited to, with respect to shapes, sizes, dimensions, angles, and distances. One of ordinary skill will understand that, in the context of this disclosure, these terms are used to describe a recognizable attempt to conform a device to the qualified term. By way of example and not limitation, components such as surfaces described as being “generally planar” will be recognized by one of ordinary skill in the art to not be, in a strict geometric sense, planar, because in a real world manufactured item a surface is generally never truly planar as a “plane” is a purely geometric construct that does not actually exist, and no component is truly “planer” in the geometric sense. Thus, no two components of a real item are ever truly planar, as they exist outside of perfect mathematical representation. Variations from geometric descriptions are inescapable due to, among other things: manufacturing tolerances resulting in shape variations, defects, and imperfections; non-uniform thermal expansion; design and manufacturing limitations, and natural wear. There exists for every object a level of magnification at which geometric descriptors no longer apply due to the nature of matter. One of ordinary skill will understand how to apply relative terms such as “generally,” “about,” and “approximately” to describe a range of variations from the literal meaning of the qualified term in view of these and other considerations.

Further, use in this description of terms such as “upward” and “downward” do not actually require that certain surfaces or objects be closer or further away from a surface upon which an exercise machine is resting at any given time. Instead, they are generally used to denote opposite directions in conjunction with the standard arrangement of the FIGS. provided herein so as to give relative positioning of elements. Similarly, terms such as “inward” and “outward”, “left” and “right”, and “top” and “bottom” are used to show relative directions or positions as opposed to absolute location.

While the invention has been disclosed in conjunction with a description of certain embodiments, including those that are currently believed to be the preferred embodiments, the detailed description is intended to be merely illustrative and should not be understood to limit the scope of the present disclosure. As would be understood by one of ordinary skill in the art, embodiments other than those described in detail herein are encompassed by the present invention. Modifications and variations of the described embodiments may be made without departing from the spirit and scope of the invention. 

1. A conveyor chain for a stepmill, the chain comprising: a plurality of links, each of said links comprising: a first member and a second member arranged together at a joint forming a generally 90 degree angle, said first member having an edge spaced from said joint a first distance and said second member having an edge spaced from said joint a second distance different form said first; a first plurality of eyelets extending from said edge of said first member, said first plurality of eyelets alternating with a first plurality of gaps, each of said eyelets in said first plurality of eyelets having a hole therethrough; a second plurality of eyelets extending from said edge of said second member, said second plurality of eyelets alternating with a second plurality of gaps, each of said eyelets in said second plurality of eyelets having a hole therethrough; and a plurality of rods; wherein said plurality of links are positioned so that: said first plurality of eyelets on a first link are interleaved into said second plurality of gaps on a second link and a rod from said plurality of rods is placed through said holes in said first plurality of eyelets on said first link and said holes in said second plurality of eyelets on said second link; and said second plurality of eyelets on said first link are interleaved into said first plurality of gaps on a third link and a rod from said plurality of rods is placed through said holes in said second plurality of eyelets on said first link and said holes in said first plurality of eyelets on said third link.
 2. The conveyor chain of claim 1 wherein said plurality of links includes at least four links.
 3. The conveyor chain of claim 2 wherein said plurality of links includes at least eight links.
 4. The conveyor chain of claim 1 wherein each of said rods extends from said eyelets on both sides of said links.
 5. The conveyor chain of claim 1 wherein said plurality of links comprises an even number of links.
 6. A stairmill comprising: a support structure; two tracks attached to said support structure at opposing sides of said support structure; and a conveyor chain comprising: a plurality of links, each of said links comprising: a first member and a second member arranged together at a joint forming a generally 90 degree angle, said first member having an edge spaced from said joint a first distance and said second member having an edge spaced from said joint a second distance different form said first; a first plurality of eyelets extending from said edge of said first member, said first plurality of eyelets alternating with a first plurality of gaps, each of said eyelets in said first plurality of eyelets having a hole therethrough; a second plurality of eyelets extending from said edge of said second member, said second plurality of eyelets alternating with a second plurality of gaps, each of said eyelets in said second plurality of eyelets having a hole therethrough; and a plurality of rods; wherein said plurality of links are positioned so that: said first plurality of eyelets on a first link are interleaved into said second plurality of gaps on a second link and a rod from said plurality of rods is placed through said holes in said first plurality of eyelets on said first link and said holes in said second plurality of eyelets on said second link; said second plurality of eyelets on said first link are interleaved into said first plurality of gaps on a third link and a rod from said plurality of rods is placed through said holes in said second plurality of eyelets on said first link and said holes in said first plurality of eyelets on said third link; and each of said rods in said plurality of rods includes a portion extending from said eyelets on each side of said links; wherein said rods include a roller bearing on each of said portions, one of said roller bearings on each rod rolling in each one of said two independent tracks.
 7. The stepmill of claim 6 wherein said plurality of links includes at least four links.
 8. The stepmill of claim 7 wherein said plurality of links includes at least eight links.
 9. The stepmill of claim 6 wherein said plurality of links comprises an even number of links. 